Matrix board



" -50 ;;tiire of from 60 isi*sdaeienguio i p nowann J.

'.BLAKE, or BOSTON,"

I 1,699,519 PATENT OFF-ICE.

MASSACHUSETTS.

HATRIX BOARD IToDrawing.

The inventionrelates to improvement in matrix bqard ,for stereotypers use. The "board as ordinarily used for stereotype purnposes is usually composed of a mixture of 5 fibre and afiller of some material, the mixture usually consisting of about 70% fibre and is usually 4 30% of a clay filler. The board ma'dedn sheet form called a mat or flong and sold to the s'tereotypers in this condition. This mat or sheet material is cut up as esired into blanks according to the size desired by the stereotyper. The impression for the matrix "is then formedin the surface the blank by suitable dies. vAfter a few casts have been taken on the matrix, the surface becomesiwornso that it is impossible to take any more good casts. The life of the matrix is usually sufficient to take only about six good'casts. 9

protective coating for the matrix qualities so it greater wearing be obtained a much greater provide a board to glve that there may number of casts. applied to the matrix board in at the factory before .it has-been cut u into blanks. for the stereotypers use and efore i; has been'subj ected to the 'matrixforming ies. Another object of the inventionis to provide this,protective coating of such a character that it will readily take the impression of the dies to form the matrix and yet be sufficiently tough so that it will not crack or i break under the forming pressure of the wearing qualconsists essentially in providing the matrix board with a homogeneous layer of cellulose xan- 40 thate; W

In producing the-coated matrix board, I proceed as follows:

Taking a sheet of 'plain matrix board as it comes from the mill; I then prepare the coating material as foll I take commercially pure cellulose preferably wood pulp and rst treat it*with a solution of sodium hydroxide, preferably a 17 .5 to 20% solution at ordinary room temperato This treatment is its sheet form Jpreferably done by immersing the cellulose in {sodium hydroxide or caustic soda and allow- ""ng it to soak in long enough to give a good ixture. jThis treatment is continued for ferably about twentyabsorbs somewhat more four houra ntil it soda,

until the mixture weighs ab weight of the original cellulose before it was treated about one-half of the arm The object of the present invention is to ,p

Preferably this coating is the use of After it is dry, the

' above described coatlng preparation gives Application filed- December '12, 1925. Serial No. 75,144.

than three times its own weight of the caustic then the excess CBAIS'GIQ, is pressed out out four times the if we start with ten pounds of the resulting. product, after hydroxide so- For "instance, pure cellulose,

being treated with the sodium lution and. after the excess caustic has been 'ressed out, should weigh'about forty pounds.

with the sodium hydroxide solutlon.

This resulting mixture is called soda cellulose and should be allowed to stand for several-days for aging purposes, preferably some hours, depending upon the variety of stock used. After it has been sufficiently aged, there is added to the mixture a quantity of carbon disulphide, preferably in weight 'ht of the original cellulose; for instance if we start with ten ounds of cellulose there should be now added about five pounds of carbon disulphide. This mixture should be agitated by stirring or by other means until the particles are all thoroughly mixed and gathered together, the time required for this bein usually about five hours. Any suitable agitating machine or apparatus may be employed for this purpose. Afterthe mixture has been suitably agitated there should be added suflicient water viscous solution to make a substantially 6% of the original cellulose. The percentage of solution may be varied according to judgment and may be more or less than 6%. t might properly be even as much as 10% or slightly more or even less than 6%. A considerable variation'may be made and still-obtain good results. This produces a cellulose xanthate solution commonly called viscose and which I use for the coating.

The solution should then it has the consistency of paint. The mixture is now ready to bea plied to the surface of the matrix board. t may be applied in any suitable wayto make a smooth, even coating like a coating of .paint'. It may be applied by a-brush or by any other suitable means, either by hand or by machine. After the coating has been applied, it should be alwed to dry in a temperature of about 68 F. board is then ready for the stereotyper s use. 7 The treatment of the matrix board with the to the board a homogeneous layer of cellul xanthate which will adhere firmly to the be diluted until a of salliulloss otherwise known as cefiulose Xan- 'i'hate. v

2. A W004i fibre fiong r mat for a matrix Llank having a surface coating of thio-carbona-t'e of eeliu10se otherwise known as celiu- 'lese zamthaie.

' 8 A papr boafimmg or mat-for a matrix a blaml; having mom-impregnatingcoating 9f What 1' claim is: thio-carbemate 0f cellulose.

1. fibrous "011g 01 451" a blank In testimony Wherefaf I In? signature, having wa tiflg comsisfing 2f 'shici sarbmmie V HQWARD: -31 

